The present invention relates generally to trail cameras and, more specifically, to trail cameras having detectors for determining when to take a picture or video.
Trail cameras (commonly called “trail cams”) are used to take pictures or videos of certain subjects, such as wildlife. In order to trigger the camera (e.g., take a picture or start a video), trail cams typically include a detector that detects that a subject is within view of the camera. The detector can detect a variety of variables, such as sound, opacity, geomagnetism, reflection of transmitted energy, electromagnetic induction, and vibration. Most trail cams used today utilize an infrared (“IR”) detector for triggering the camera.
On an IR trail cam, the IR detector is positioned to receive radiation from the direction that the camera is pointing. A lens (e.g., a Fresnel lens) can be positioned in front of the IR detector to gather IR radiation and define a field of view. The detector will trigger the camera when a subject is detected in the detector's field of view. Typically, the detector's field of view is the same as the camera's field of vision so that an object sensed by the IR detector is within the field of vision of the camera. When the IR detector senses a change in the IR radiation within the field of view, it sends a signal to activate the camera.
Because the detector's field of view is the same as the camera's field of vision, pictures taken with the above system commonly result in the subject (i.e., the object emitting IR radiation) being positioned on the edge of the picture. In order to solve this problem, some cameras design the detector's field of view to be narrower and centered with respect to the camera's field of view. The result is that the detector does not trigger the camera until the subject is more centered within the camera's field of vision.